I. Field of the Invention
The present invention relates generally to switch devices for switching the positions of railway tracks in order for trains to move from one track to another. More particularly, the present invention relates to an electric motor driven switch machine having a low vertical profile while retaining all of the functionality of existing switch machines.
II. Description of the Prior Art
It is a requirement for operation of a railroad network to have the capability of switching railroad trains from one track to another. A common method of providing this switching capability is to install an electric motor driven switch machine along side of, and interconnected to, a switch point of a railroad track. These switch machines often have one or more manual operations for shifting the position of the track without the use of the electric motor for certain situations, such as when electric power is not available.
Two manual operations typically integrated within switch machines are the hand crank and hand throw operations. The hand crank operation permits operational personnel to switch the track at the switch point by turning a hand crank for maintenance and installation purposes. The hand throw operation permits operational personnel to switch the track, i.e., throw the switch machine, at the switch machine when control signals from a remote control facility are not able to reach the switch machine.
Conventional design practice has been to place a hand throw means for controlling the hand throw operation above one of the drive shafts of the switch machine, such as the crank shaft. This practice not only creates an undesirable bump in the top profile of the machine, but also contributes to the high vertical profile of existing switch machines.
A switch machine having a low vertical profile and no projections extending from its top surface is desirable for many applications. Particularly for transit applications, it is essential that a low profile be maintained by a switch machine in order to Clear steps, third rail electric pick-ups and other types of ground clearing equipment extending down from a transit car or locomotive.
A low profile switch without overhead projections is also desirable for additional safety and maintenance reasons. The switch machine is subject to all manner of damage due to its harsh environment. For example, vehicles or objects that may contact and damage the switch machine include rail maintenance equipment, snow removal means, foreign objects falling off trains, local car and truck traffic in the area and other objects passing through or over the general vicinity of the switch machine.
There are known in the art switch machines that are submersed within pits or covered with protective structures. These switch machine designs lower the vertical profile and provide added protection to the switch machines, however, require a longer axial length and are difficult to install within the ground layouts of existing switch machines.
Accordingly, it is a primary object of the present invention to overcome the aforenoted problem associated with designing a switch machine having a low vertical profile while retaining all of the various capabilities of existing switch machines, including the electric motor, hand crank and hand throw operations.
Another object is to provide an additional vertical shaft for the hand throw operation that is independent of, and horizontally adjacent to, any other vertical shaft of the switch machine, in order to reduce the height of the switch machine.
An additional object is to provide a switch machine having no projections extending from its top surface in order to clear various types of ground clearing equipment extending down from passing vehicles.
A further object is to provide a switch machine disposed or situated within the confines of the ground layouts of existing switch machines in order to facilitate the installation of the switch machine within existing railroad networks.
A still further object is to provide a switch machine having a low vertical profile for safety in order to avoid various hazards that pass through its general vicinity, without the need of an additional protective cover.